Push bench drive



Jan. 3o, 1940.

S. SMITH PUSH BENCH DRIVE Filed June 18, 1938 Patented Jan. 30, 1940 PATENT OFFICE,

PUSH BENCH DRIVE Sydney Smith, London, England, assignorA to Wellman Seaver Rolling Mill Company Limited, London, England, a company ol'k Great Britain vApplication June 18, 1938, `Serial 214,559

. In Great Britain June 21, 1937 u 8 Claims. `This invention relates to' apparatus for the `manufacture of metal tubesandv other tubular metal articles.

The apparatus is'y of the push bench type by which a somewhat thick cup-shaped hollow billet ycarried on anend of a mandrel'is pushed through Adies or through passes betweenrolls which decrease successively in cross-sectional l area in thev forward direction, whereby the billet 10 is reduced ini thicknessand-spread out length-I wise along the mandrel until the billet is brought to orapproximately to thefformvof atube of the required'thickness and' length.)A An example of such apparatus is describedin 'the specification i er British Letters Patent No. 300,288. The in-` y yner end of the mandrel is engaged with a mandrel carrier which' in turn is carried or supDQrted by adriving' rack by which it and the mandrel .are moved forward and retracted, the raclrbe-l ing drivenxby a driving pinion which in turn is operated by a ldriving motor. A large tube ,re-

quires a greater pushing force to drive it through the. dies than a smaller tube and consequently a smallertube can be produced at a greater drawing speed than a larger tube. Further, as

it is usual to'elect a greater reduction of crossper unit of time, for example one hour, depends,v 3 for a particular size of tube 'largely on the rate at which the motor armature together -with'the` movingypartsof the push bench apparatus will accelerate `to full speed and decelerate toy rest in both the forward and'returnstrokes of the 40 rack.

ion through a reduction gear, av direct `current motor being employed `because itcan be ,readily adjusted to theA different speeds at4 which dii-v ferent sizes of tubes have to vbe produced ona single drawing apparatus and further it will givev a high starting torque. Also a direct current motor willgive a constant .torque while acceleratward' drive, l and will provide a constant power output;l '.As`.,'l1ewever, v the supply usually al- Usually the driving motoris a direct current-` electric motor which drives the rack driving pin- (Cl. 205`4) f .y

yternating.v current, a motor generator or other convertingapparatus has to be included in the. plant. v 1 n To drive the push 'bench apparatus, the motor has to be large sc thatin some cases the energy t" absorbed `in accelerating the `armature to its? full speed may be fromk 4 to 6 times, that re,-v quired tc accelerate and drive thel other moving parts ofthe apparatus, that is from.75 to -of the power of the motor is absorbed'in accelerating its armature; Thus the time of apushing operation is dictated ultimately by the inertia of the motor armature. lTo provide the necessary torque .for accelerating the armature and 'the moving parts of the bench, the motor has to have a constant torque characteristic from rest to vits rmaximum forward speed, whereas it` would generally be preferable forthe 4motor to provide a constant horse power.

The .present invention has' for objectto provide driving means forpush bench drawing appara-tus in which-,inertia losses in thev driving means/are ygreatly reduced and consequently the size 'of `the vdriving motor may be reduced, capitalfandmaintenance costs will be reduced, shocks vtransmitted to the tube being pushed will be reduced and a better Atube will result, the output of the push bench4 will be increased, andthe pushing speeds will be automatically reduced at high loads and increased at light loads', as with different sizes of tubes, or with load' variation during completion of the pushingl stroke or shouldy the material be hotter atone time than another.

The present invention comprises the combi'- nation. with pushbench drawing vapparatus of driving means therefor comprising a drivingmoton-an rhydraulic torque converter connected to ysaidmotor and a reversing gear connected between the output shaft of the converter and the moving element of the push bench apparatus. In this combination, the torque converter'permits ofthe use of'a smaller motor, because it may be run at constant speed, eliminating the aforesaidl problems of armature-inertia power-consumption. Themotor need essentially be large enoughv v.only to provide power for accelerating the parts beyond the converter. Owing to the presence of the said converter, entra power for accelerating the motor itself is not requiredrand the motor vmay consequently be made of smaller size than hitherto.

Furtherfeatures of the invention will appear from 'the following description, by way of example, offan embodiment of the invention illustrated'in the accompanying drawing, in which: 55`

final gear drive 4. From the latter the usual" rack 5, which moves the mandrel through the mandrel carrier, is* driven through a pinion 6 or pinions.

The driving motor I may'beeither a direct current motor or an alternating current motor and, if the latter, is conveniently. an induction motor. n

The hydraulic torque converter 2 may be of any convenient known type. A satisfactory-type consists essentially of a centrifugal pump, driven by the motor I, which supplies liquid toy a tur-' bine whose rotor is connected to the shaft 8,

and thus to the reversing .gear 3. The blades ofthe pumpare adjustable' to permit of variation'of the speed of supplyof the liquid to the turbine or of vcomplete cutting olf of the said supply. The blades maybe adjusted manually, for. example by the handle 'I, or by means of a servo-motor controlled, for exampleby a cam,

so as to cause the speed' of the output shaft 8` o f the converter to `follow a predetermined speed range. For instance,;an example of a torque converter. with adjustable blades is disclosed by U. S. Patent No. 1,900,l120 .of March '7, 1933;

In thel reversing gear illustrated in Fig. 2 the'output. shaft 8 of the converter is connected by reduction gearing 9 to'a shaft I0' which, for the forward drive, can be coupled -by a clutch.

I I to ashaft I2 connected to the final drive 4.

For the reverse drive, a shaft I3 connected to,

the shaft IIJ throughgear-'Wheels I4, I5 on the said shafts and an intermediate Wheel` vI5 canv be/coupled by a clutch I'I to a gear-wheel I8 which is free von the shaft ,i3 and meshes with a gear-wheel I9 on the shaft I2.

clutches; are arranged` to be operated by forks 20, 2-I manipulated-togetherfrom a handle 22..y Between extreme positions in which one clutchis engaged and the other disengaged there is and intermediate neutral position, shown in Fig. 2.

With reversing -gear vof this kind,l the reversef:

drive transmitted may havea higher. ratio than the forward speed in any appropriate relation.

In'the operation of the-abovedescribed driving means, the motor I, When'started, continues to run at a more or less. constant speed. The. speed of the output shaft 3, of the torque con-.

verter 2 automatically varies inversely as the powerrequiredf in the operation of` the push bench from instant to instant. Thus the speed of theshaft il increasesas the power required, The

by f the rack 5 decreases .and vice versa. clutches of the reversinggear are operated at theappropriate moments to cause the rack to j travel forwards and rearwards. i

To start a forward stroke of the rack 5, thev clutch II is engaged while the torque converter 2 is in a condition of adjustment in whichits output'shaft 8 is stationary or substantially sta-A tionary, sothat the clutch is engaged under light `load conditions. After this engagement of the clutch II, the torque. c onverteryis adjusted so that poweris transmitted to the shaft 8` 2,188,822 and thence through the gearing, 4,' 6 to the rack.

s The movable.- parts of the clutches II, I'I, for instance coil The latter rapidly increases its speed, since the only parts to be accelerated, in addition to the said gearing, are the moving parts of the bench,

i. e., parts on the output side of the torque converter. At the end of the forward stroke ofthe Y rack`5, thev converter is adjusted so thatv its output side is-allowed to slip in' relationto the input side,-that.is to fall off-` in speed, whereupon the torque from the drivingmotoris destroyed,v S/ almost immediately. Before the rack has come .to rest at rthe .end of the forward stroke, the i' `clutch I'I is disengaged and the otherclutchI'I i is engaged.' "Ihetorque converter is then adjust'ed so that-power is again transmitted from.

the motor I tothe output shaft 8, but in the opposite direction. 'I'hus the rack and other mov-- ing parts ofthe bench may be arrested by using the converter as a .brake until the inertia of 4 the'said parts is destroyed, whereupon therack will at lonce start its rearward stroke.4 A similar reversal/isperformed at the end Aof this v stroke.

In some cases, it may be advisable'to. provide 'aflywheel between the motor I and torquekcon'- verter 21toensure a smoother` drive'and also;

possibly, to permit of a furtherfreduction inthe size of the motor. To permit'of a braking effect-being- `exerted upon the rack independently of the braking ef-l fectfwhich can be produced, as v.explained above`,'

by'the torque converter, a brake'of appropriate type may be'providedbetween thereversing gear.

3 and the` rack pinion 6L I "Types of 1.elefslggear other than vthat illus-I' traf/Cd may be emp10511ed. l e l l The combinationwiththe mandrel `and :refl ducing means of tube-making push-bench apparatusof driving means for driving the mandrel.' on which vthe tube is formed, throughfthe re'-` ducingfmeans, comprising a drivinggmotor, an

hydraulic torque. vconverteiconnected to 'the said motor and\ a reversing. gear connected betweenthe output side vof vtheconverter andthe moving element of thepush-bench appaartus.l y l, 2. Driving meansin accordance withv claim v1, wherein the driving motoris analternating current motor which runs at substantially constantv speed, preferably v an induction motor.

3. Driving means in accordance with claim 1,. wherein-.the torque converter is of the type consistingY essentially of javdriven centrifugal pump anda driving turbine supplied with liquid by.

the pumpwhoseI blades are adjustable for cony trolling the supply of'fliquid tothe turbine.

14, Driving means in yaccordance withclaim 1, wherein afflywheel is arranged betweenithemotor and torque converter. 5. Driving means in accordance o'f lthee-preceding claims, whereinV the reversing gear is aj clutch-.controlled mechanicalv gear.

5,Driving 'arrangement-for ya tube-I nakin'gi` with any one;

push-bench apparatus, comprising. a driving moton-an hydraulic torque converter kconnected to thesaid motor and l `a reversing gearI connectedj tothe output side ofthe said converter.

7. In a tube making push Abench apparatus;

wherein .the mandrel is 'pushed forward by a.

reciprocatory driving rack,` actuated on its forcing and return strokes by a meshing rotary'pin'- ior 1; a drive forfsaid pinionr including a rotary eletric motor, an hydraulic torque converter con'..

nectedwith and drivenby said motor, and. me-

Channel, retreinegear wenn@ withad driven.

by said converter and operatively coupled to said pinion for driving the same.

8. A tube making push bench apparatus including a mandrel forcing reciprocatory rack bar and its driving pinion, a drive for said pinion including a prime rotary motor, an hydraulic torque converter operatively coupled to and driv en by the motor, and mechanical reversing gear with controlling clutches operatively coupled to and driven by said converter and operatively coupled to said pinion for driving the same.

SYDNEY SMITH. 

